Several electrically driven hand-held grass shears are on the market. In general, they have a fixed base plate having a plurality of spaced teeth projecting forwardly from the tool and a cutting blade which is pivoted at its middle section and driven at its rear end for arcuate reciprocation with respect to the base plate. This driven blade also has a plurality of teeth, usually one less than the base plate, and movement is limited to the distance between two adjacent base plate teeth. The grass which enters between the teeth of the base plate as the tool is moved forwardly is cut by a shearing action.
As the teeth of the cutting blades become dull with use, they may be sharpened or the entire blade may be replaced. This operation has required the removal of the base plate or equivalent operation. The disassembly, blade replacement and reassembly, while relatively simple operations, are sometimes beyond the limited capabilities of the users of the equipment. Also, the time required frequently means that the tool is operated with a dull blade with consequent poor performance.
The electrically driven shears must be regarded as inherently dangerous. Great care must be exercised in their use. In spite of safety catches usually provided, there is also the danger that a curious child will pick up the tool from its storage place and manage to close the switch and possibly be badly injured.
One of several objects of the present invention is to provide an electrically driven grass cutter which operates with a combination sickle and shear action giving superior results. More specifically, a cutting blade having a single tooth accelerates rapidly and attains high speeds in passing over the fixed teeth to cut with a sickle action as well as with shear action involvement.
An object of prime importance is the provision of a grass sickle-shear which is so constructed that the cutting blade may be removed and replaced with a new blade in a matter of seconds and without the use of tools. Another object is to provide for the ready replacement of the wear part of the drive mechanism. This is accomplished by providing a blade-slide subassemmbly as a replacement part.
A related object of great importance is to provide an electrically driven grass cutter from which the cutting blade may be so easily and quickly removed that it is feasible to keep the blade in a safe and separate place while the machine is stored so that the danger of injury to children is completely eliminated. Only seconds are required to replace the blade in the machine to ready it for use.
A further and important object is to provide a grass cutter of the type described wherein the radius of arcuate reciprocation of the cutting blade is maximum whereby the tendency to push grass stems out beyond the teeth rather than to cut them is minimized.
Other features of operation and construction of the electric grass sickle-shear will become apparent as the following detailed description proceeds.